Definition of energy

Energy is a propety of objects which can be transferred to other objects or converted into different forms.The "ability of a system to perform work" is a common description, but it is difficult to give one single comprehensive definition of energy because of its many forms. In SI units, energy is measured in joules.

Types of energy

• Mechanical: the mechanical energy is the sum of  kinetic and potential energies. Kinetic energy is the energy associated with the bodies that are in movement, it depends on the mass and the speed of the body.The potential energy is the energy that results from the position or configuration of the object.

• Nuclear: the nuclear energy or atomic energy is the energy that is released spontaneously or artificially on the nuclear reactions.

• Electric: the electric energy is the form of energy that will result of the existence of a potential diference between two points, situation that will permit establish an electrical current between both points if you place it in contact trought an electric conductor to obtain the mentioned work.

• Radiant: the radiant energy is the energy possessed by the electromagnetic waves like the visible light, the radio waves, ultraviolet rays (UV), infrared rays (IR), etc.

• Thermal: is known as thermal energy the energy released in form of heat, that is, it passes from a warmer body to other with less temperature.

• Chemical: the chemical energy is the energy contained in molecules.

Energy transformation

Energy transformation or energy conversion is the

process of changing one energy transformation to another form of energy.

Renewable energies

The renewable energies are those that are present in an unlimited form or that are regenerated. They are: solar, geothermal, hydroelectric, nuclear, wind, biomass and tydal. These energy sources are usually more clean than non renewable energies.The following slideshows explain these energy sources and how their power plants work:

Authors: Pablo Trasbach, Sonia Mª Romero, Antía Ramallo.

Authors: Álex Tubío, Sara Romero, María Blanco.

Authors: Eva Regades, Jorge Saavedra, Miranda Carou.

Authors: Jorge Hermo, Jorge Piñeiro, Catarina da Silva.

Authors: María Jacobs, María Gómez, David Triñanes.

Authors: Laura Pérez, Pablo Manuel Piñeiro, Sabela Martínez. 

Non renewable energies

The non renewable energies are those that are present in a limited form. They are fossil fuels like oil, coal, gas and nuclear fuels like uranium. These energy sources were the most used until a few years ago, but now they're less used because they are poullants, especially, the fossil fuels.The following slideshows explain these energy sources and how their power plants work:

Authors: Yolanda Caqueiro, Álex Santos, Javier Varela.

Authors: Sandra Martínez, Roi García, Sara Blanco.